1. Field of the Invention
The invention concerns a new duckbill valve of improved performance and lower manufacture cost than traditional ones.
2. The Related Art
Duckbill valves are utilized to regulate pressure in a host of devices spanning many industries. Applications for these devices are found in automotive brakes, small home appliances, kidney dialysis, hypodermic syringes, sporting goods, toys, non-aerosol pumps and a variety of industrial equipment. Their popularity stems from their simple construction. No moving parts are present other than the rubber housing itself.
Despite their simplicity, antiquated manufacturing processes have rendered the traditional duckbill valve relatively expensive. Standard manufacture employs compression molding of a rubber followed by a second separate step of cutting a slit into the molded rubber valve. This two step procedure slows production and adds cost.
U.S. Pat. No. 5,010,925 (Atkinson et al.) assigned to Vernay Laboratories, Inc. discloses a more sophisticated version of a duckbill valve assembly. In one embodiment (FIG. 6), an outer wall of the valve body is formed in an oval shape. Insertion of the oval body into a circular recess of a valve fitting biases tapered lips 38, 40 together to close the valve assembly. Unfortunately, the V-shaped tapered walls intersect only at a relatively narrow contact point. This results in a less than robust seal.
Accordingly, it is an object of the present invention to provide a duckbill valve having a stronger seal.
Another object of the present invention is to provide an improved duckbill valve manufacturable in a single process step.
Yet another object of the present invention is to provide a duckbill valve of less expensive construction.
Still another object of the present invention is to provide a duckbill valve having improved longevity and performance.